In order to achieve the desired efficacy for certain pharmaceutical medicines, there exists a persistent and ongoing need for first selecting the correct medications for addressing a particular disease, and then titrating those medications over time to make sure an individual is receiving the proper dose. Not only is this problem created by the nature of a particular disease, it might also be compounded by a patient's particular response to a particular medicine, where the latter is attributable to a host of factors, such as the patient's unique genetic composition, gender, degree of affliction, diet, weight, smoking status, or other factors that might mitigate efficacy of a specific medicine. Accordingly, the titration necessary to optimize efficacy is highly dependent on the individual, and often times, clinical plans are too generic or overbroad, and fail to sufficiently account for individual responses to a particular dosage.
There are a number of studies that have shown how the level of drug in a patient's blood stream varies for the same dosing depending upon the individual patient's genetic composition and personal attributes. Various mathematical models have been established by studies and can predict bloodstream concentrations of particular drugs in response to particular dosing in individual patients based upon factors relating to the patient's genetic factors and personal attributes.
Despite the availability of accurate models in the art to evaluate a patient's reaction to dosing based upon genetic factors and personal attributes, actual practice remains rooted in trial and error aided by basic information and time honored dosing strategies. Doctors can consult, for example, the dosage recommendations and induction protocols provided by pharmaceutical manufacturers. Common induction protocols are also favored, such as, in the example of the anticoagulant warfarin, the popular “10-7-5” protocol in which dosage begins at 10 mg, moves to 7 mg and then down to 5 mg. Doctors administering medicine are unlikely to consult any models or conduct any calculations based upon genetics and personal attributes, and a tool is not provided to aid dosing. Blood tests, such as the PT/INR test to check blood coagulation, are conducted frequently until a stable level is achieved. Doctors adjust dosage in response to monitored patient response. The adjustments selected and the timing of the adjustments can vary significantly from doctor to doctor.
As such, patients frequently receive either too much or too little of a needed drug as doctors and clinicians “over-steer” in an attempt to administer or prescribe the correct dosage. Adverse drug reactions are a leading cause of death in the United States, with over 100,000 deaths per year and over 2.2 million hospitalizations per year.
For example, in anticoagulation clinics, patients may be administered warfarin in an attempt to regulate over-coagulation caused by various thromboembolic diseases. Warfarin is the most commonly prescribed anticoagulant, but unfortunately, its complex dose-response relationship presents an ongoing challenge to its safe and effective use. Typically, patients visit an anticoagulation clinic on a specific schedule, such as every 24 days, to have their status monitored and have dosage adjustments made, if necessary, to the patient's “maintenance dose.” However, the pharmacological response to warfarin is delayed, making it difficult for a doctor to determine whether the adjustment has accurately corrected the dosage, or has overcorrected the dosage to the point where the patient will end up over-anticoagulating or sub-anticoagulating.